Thermostat



F. H. KOLBE AND E. R. DE LUIZ.

THERMOSTAT. APPLICHON FILED MARa 21,1919. 1,41 6,722. Patented May 23, 1922,.

UNITED STATES PATENT OFFicE.

FREDERICK II. KOLBE AND EDWARD R. DE LUIz, OE DETROIT, MICHIGAN, AssIGNORs To RELVINATOR CORPORATION, or WILMINGTON, DELAWARE, A' CORPORATION OE DELAWARE.

THERMOSTAT.

Specification of v`Ilietters Patent. Patented May 23, 1922.

- Application' led March 21, 1919. Serial No. 284,039.

To all inkom/it may concern.'

Be it known that we, FREDERICK III. KOLBE and EDWARD R. DE Luiz, citizens of the 'United States, residing at Detroit, in the county of Wayne and State of Michigan,

have invented a certain new and useful Improvement in Thermostats, of which the following is a full, clear, andexact description,

The objects of the invention; are the pro-v vision of a simple and compact device lwhich while small in total size shall possess an extremely large operating chamber; the provision of a :thermostat ofthe volatile fluid type which shall combine the possession of a large volume of the volatile agent whereby 'powerful action is produced, large exposed surface whereby promptness of operationl is secured, and provisions whereby its motion isres'trained to a small compass so as to prevent linjury by extremes of temperature aboveor below the range for which it is intended. Other objects are the provision of a device whichis easily and. simply maIiufactured, easily adjusted and free from dis- ;lorders; the provision of improved means for associating it with the surrounding and cooperating objects; while further objects and advantages of the invention will become apparent as the description proceeds.

In the drawings accompanying and forming a part of this application we have illustrated certain physical forms in which our invention may be embodied although it will be understood that these drawings are intended to be illustrative only and not to limit us to the particular details therein shown. In these drawings Fig. 1 is a vcrtical sectionalview of one form of the device corresponding approximately to the line 1-1 of Fig. 3; Fig. 2 represents a side ele vation of the same device, th'switchblock-A being shown in section; Fig. 3 yis a topvplan view of the device shown in Fig. 1; ig. 4 isa vertical sectional view showing a modification; and Fig. 5 is a detail view showing the preferred mode of applying our improved thermostat to a" refrigerating apparatus.

Referring first to FigQ, we have for purlposes of illustration shown a 'corner of an' i ordinary domestic refrigerator having a brine tank and cooling coil located in the chamber-ordinarily provided forice. This refrigerator n.comprises an external'^ rectan- \,gular casing l having therein an upright partition 2spaced `from the top as shown to provide an air passage 3, and also spaced from thebottom (not shown) to provide another passage in the well known manner. The chamber 4 defined at one `side of the partition 2 is employed for the storage of food, and the chamber 5 at the other side of said partition constitutes a refrigerant space the upper part whereof is ordinarily em'- ployed for ice which is supported u on a,

partition 5a in such wise that the circu ating air can pass over and around the same.

In this ice space we have'shown a metal.

brinetank 6 having therein an upright pipe coil 7 through which is ,pumped the refrigerant fluid, which preferably consists of a low boiling point fluid. The upper part of .this coil is preferably constricted in size as shown at 8 to form a space for the reception of our improved thermostat. It will thus be seen that-theupper end of the exposed portion of the coil is the part first contacted by the air which enters through the passage 3, and the uppermost turns of the coil are preferablylocated closely adjacent to each vother so that this entering air shall have Very little direct access to the thermostatic vessel. The device., shown in Figs. 1 to 3 includes a supporting cap 10, circular'in plan, andl of proper size and shape to fit upon the top ofthe coil 8, byv which it is supported. `This cap has a spiral peripheral flange 11,` which fits uponthe upper convolution of the coil,

the angle ofthe vflange 11 corresponding to' the pitch of the coil, so that the cap `will rest flatly thereon, and be supported with its axis substantially vertical. This cap also prevents direct impingement of the entering air upon the-thermostatic vessel.

This cap has a plurality of depending iingers 12 on its under side, the lower ends of which form abutments for the top plate 13 oan expansible vessel 14. rllhis vessel is of the well-known metallic bellows construction, comprising a circumierentially-corru: gated, longitudinally-expansible, cylindrical sheet metal wall with rigid en-ds forming a closed receptacle for volatile iluid. rlhe lower wall of the vessel is indicated at and has secured to it the rods 16 by which it is connected to the arms oi a movable spider 17 'which is located between the cap 10 andthe top wall 13, said arms projecting between the lingers 12. The head 17 carries a rod 18, which works through a hole in the cap 10', and has a. collar 19 to limit its downward movement. The rod is threaded as iiidicated lit 20, above the collar, and this threaded art receives a mit 21 to which is fixed the ower end oit a coil tension spring 22, the upper end` of which is iii-red to a collar 23 which inaycbe turned in its seat in a cap 24 fitting upon the upt er end of a spacing tube 25, which encloses the spring and which rests at its lower end upon the top of the cap 10, the upper end of the rod 18 passing freely through an opening in the collar 23.-

The upper end of the rod' 18 ispivoted at 26 to a lever 27 which is fulcrumed at 2 8 to a bracket 29, supported on the casing. The outer end of the lever is torked as shown at 30, and engages a slot 31 in an adjustable nut 32 to which is attached the screw rod 33,.

which reciprocates through the top of the switch casing 34. The lower end of this rod is operatively attac-hed to the switch mechanism so as to close the circuit when it is depressed and open the circuit when it is elevated. Any suitableor convenient kind of switch mechanism can be employed, wherefore l have not .indicated any detail construction except that the same is prefer-.

ably housed'in a hollow casing 34 of insulating material mounted on an extension 35 at one side of the cap 10 and connected to the lead wires 36 by means of a separable plug 37. In the construction shownv in F ig. 1 the cap 24 is extended towcover and einbrace the switch casing 34 as well as the tube 25 and is' a'pei'tured for the recept-ion of a boss 38 formed on that casing. The bracket 29 is also apertured for the same boss, while the bracket, cap, tube, and casing are all held in place by the single screw 39. This detail construction is not, of course, essential tox our invent-ion but it is valuable 4in practice.

In the modification shown in Fig. 4 the construction is similar, except that a compression spring 22a is used, instead of the tension spring 22. Thishas some advantages as a compression spring is easier to adjust. This compression spring is confined .temperatures head` 1T, rod 18 and lever 2'4"' 'to the movable i switch member, and when the device is prop` efly set according to the 'temperature desired, the motor circuitwill be opened by the spring 22 when the vessel contracts a predetermined amount owing to 'the decrease in vapor tension inside the vessel, and closed by its' expansion on increase of such vapor tension., beyond the ability or the spring to withstandit. The expansion and contractionoi" 'the vessel is therefore always restricted within a narrow rai-'ige and opera` tion of the switch occurs at 'the same points, the temperature orf such operation dependn ing upon the tension or the spring 22. In. the form shown in F 1 this tension may be varied by turning 'the collar which rotates the spring 22 and with it the nut 21 which rides up or down on the rod 18 accordingly. ln the form shown in Fig. the rotation 'or' t-he nut 21LL acts'upon the spring directly.

Extremes of temperature have no injurious effect, either upon the vessel or upon the spring; forupon excessive heat, the expansion of the vessel is arrested by the collar 19 at a point within the elastic limit of the spring and upon excessive cold, the contraction of the vessel is arrested by the fingers 12, .the spring being absolutely freed from strain. rl`he last named feature is particularly important in a thermostat for retrigeration use as rendering it sal'e against high which may occur either through accidental failure of the operating current or by reason of shipment, installation or adjustment in hot weather.V

'The cap 10 serves to protect the expansion chamber from the direct impact of the inflowing warm air and restricts the heat exchange largely to the side walls of the same. As a consequence, during the operation of the refrigeratinp motor (not shown)` the brine tank 6 will lirst become very .thoroughly cooled after lwhich the coil 7 will become covered with frost up to and sui'- roundiiig t-he vessel 14 whereupon sufficient heat will be abstracted from that vessel to reduce the vapor pressure of the fluid there.- in and permit the spring 22 to o en the switch and stop the motor. The siielding effect of the coil 8 and cap 10 prevents the thermostat from absorbing an amount of heat necessary to expand the vessel and close l the switch until the. coil 8 has become quite thoroughly warmed up, undue elevation of the temperature in the provision chamber 4 being meanwhile prevented by the large heat ed and arranged to oppose suc rangement we, have been able Ito increase very markedly the length of the idle periods of the motor and thereby 'save operating oost without endangering the refrigerating capacity of the machine. Also as above stated the large vo-lumetric capacity of the` vessel 14 leads to a very prompt and positive operation while'the features of construction which have been specifically pointed out prevent injury of the device by excessive tem-' peratures. We have shown the bottom plate 15 as provided with'a iilling opening closed l by a screw-plug 40.

We do not restrict Vourselves to the detail constructions herein shown except as recited x the prior-- in the' claims and necessitated by. art.`

Having thus described our invention, what we claim is 1. The combination of a supporting plate having on one side a plurality of spaced abutments, a longitudinally expansible vessel having one end presentedl against said abutments, a head located betweenlsaid plate and vessel and having cavities for said abutments, connecting means betweensaidhead and the further end of the said vessel, a controlling device mounted upon the opposite side of said plate, and operative connections between said head and controlli-ngdevice. j

2. In a device of the character described,

vin combination, a pair of interitting, relativelymovable members, one having abut' ments and the other connecting devices, a longitudinally expansible vessel having its nearer end engaging said abutments and its 'further end connected to said connecting devices, acontrollin devlce carried by one of said members an operatively connected to the other member, and a single s ring adaptmovement between said members as occurs upon the elongation of said vessel.

3. .TheF combination of a cap havingdepending projections on its under side, a head movable :up and`down between said projections, an e'xpansible vessel abutting at one end against said pro'ections, connections be ltween the other` en of the vessel and the head, an electric switch mountedupon the ca and an operating connection between said head and the movable member of the switch.

44. The combination of a cap having depending projections on its under side, a head movable u and down between said. projections, a ongitudinally expansible vessel abutting at one end against ysaid projections, connections .betweenthe other end of the ves'- sel and the head, an' electric switch mounted upon the cap, and an'operating connection between said head and the movable member of the switch, said connection including a rodv extending throughthe cap, and a spring connected to the lrodand tending to contract the vessel.

5. The combination of a cap having spaced abutments on one side thereof, la longitudinally extensiblel cylindrical vessel 'one end of which is seated against said abutments, a head movable axiallyl with respect to the cylinder betweenI the abutments, a connection outside the c linder between the other end thereof and t e head, arod projecting from the head through the cap, a spring attached' to the rod and` tending to contract the vessel, a switch'supported on the opposite side ofthe cap,`nand an operating connection between the rod and the switch.

l 6. The -combination with a circumferentially corrugated, longitudinally eXpansible,

cylindrical, sheet-metal vessel having sealed ends, of a head overhanging and spaced from one of said ends, connecting means between said head and the opposite end, a support located above andspaced from said head, abutments carried by'said support and engaging the first mentioned end of said vessel,

an operating rod attached to said head, spring means connected to saidrod and sup- ,port and opposing the elongation lof said vessel, a controlling device carried by said support and operative connections between said rod andl evice. l

7. The combination with a circumferentially corrugated, longitudinally expansible, cylindrical, sheet-metal vessel, having sealed ends, of a head overhanging and spaced from one ofsaid ends, connecting means between said head and the opposite end, a supporty located 'above and spaced from said headand having a hole over said vessel, abutments carried by said support and engaging said vessel, `a rod connected to said head substantially 'coaxial with said vessel and passing through said hole, a spring operatively connected to said rod and opposing the expansion of said vessel, a controlling device car- 8. The combination with a circumferem.

tially corrugated, longitudinally expansible, cylindrical, sheet-metal vessel having sealed ends, of a head overhanging and spaced from one of said ends, tension means connecting said head with the opposite end, a "support located. above and spaced from said head and lhaving a hole over said vessel, abutments carried by said support and engaging said vessel, a rod connected to said head substantially coaxial with said vessel and passing through said hole, engaging projections carried by said rod and support for limiting the expansion of said vessel, a controlling device carried by said support, and operative connections between said head and device. v

9. In combination, a cap having a hole and a lurality of fingers arranged around'said ho e, a head having cut-away portions for the passage of said fingers, a rod connected to said head and passing through said hole, a vessel which is expansible in the direction connectedv to said rod and opposing the extension of said Vessel, and an electric switch l0 operatively connected to vsaid rod.

In testimony whereof; We hereunto affix our signatures.

FREDERICK H. KOLBE. EDVVARD R. DE LUIZ. 

